1. Field of the Invention
The present invention relates to a tubular vibration-damping device that is suitably used as a member mount that is mounted on an attachment part or the like of a subframe or suspension member in relation to a main body of a vehicle, a vibration damping bush mounted to an attachment part or the like at a vehicle body side of a suspension member constituting a vehicle suspension mechanism, or the like.
2. Description of the Related Art
From the past, as one type of vibration-damping device, a tubular vibration-damping device for which an inner shaft member and an outer tube member are coupled by a main rubber elastic body has been known. In specific terms, a tubular vibration-damping device is shown in Japanese Unexamined Patent Publication No. JP-A-6-129461, Japanese Unexamined Utility Model Publication No. JP-U-5-077637 and the like. Also, with this kind of tubular vibration-damping device, for example, while an outer tube member is press-fitted and fixed to a mounting hole provided on an automobile suspension member, by fixing an inner shaft member to the main body, this is used to do vibration-damping support of the suspension member on the main body.
However, with the tubular vibration-damping device as described above, for reasons such as making it lighter, reducing manufacturing costs and the like, it has been attempted to use outer tube members made of synthetic resin rather than outer tube members made of metal.
However, with the outer tube member made of synthetic resin, because of permanent set-in fatigue due to heat or changes over time, it was difficult to obtain stable press fitting fixing force on the mounting hole over a long time, and it was difficult to ensure sufficient pull-out resistance force in the axial direction.
As shown in JP-A-6-129461 and JP-U-5-077637 noted above, to ensure pull-out resistance force in the axial direction with the outer tube member made of synthetic resin, a constitution has also been proposed for which a locking projection provided on an outer circumference surface of the outer tube member is locked on the end surface of the mounting hole. However, when an attempt is made to enlarge the projection height of the locking projection to increase the pull-out resistance force, there are cases where the locking projection becomes an obstacle when inserting the outer tube member in the mounting hole to mount it, and it was difficult to obtain sufficient pull-out resistance force with the locking projection.
In particular, when a stopper rubber is provided projecting in the axial direction, and a load in the axial direction is applied via the stopper rubber in the direction for which the outer tube member can fall out from the mounting hole, it is even more difficult to ensure pull-out resistance force of the outer tube member from the mounting hole.